另一个答案将非常相似，但不需要设置TextView的文本两次

TextView TV = (TextView)findViewById(R.id.mytextview01);

Spannable wordtoSpan = new SpannableString("I know just how to whisper, And I know just how to cry,I know just where to find the answers");        

wordtoSpan.setSpan(new ForegroundColorSpan(Color.BLUE), 15, 30, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);

TV.setText(wordtoSpan);

当我试图理解一个新概念时，我总是发现视觉例子很有帮助。

背景颜色

SpannableString spannableString = new SpannableString("Hello World!");
BackgroundColorSpan backgroundSpan = new BackgroundColorSpan(Color.YELLOW);
spannableString.setSpan(backgroundSpan, 0, spannableString.length(), Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
textView.setText(spannableString);

前景颜色

SpannableString spannableString = new SpannableString("Hello World!");
ForegroundColorSpan foregroundSpan = new ForegroundColorSpan(Color.RED);
spannableString.setSpan(foregroundSpan, 0, spannableString.length(), Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
textView.setText(spannableString);

结合

SpannableString spannableString = new SpannableString("Hello World!");
ForegroundColorSpan foregroundSpan = new ForegroundColorSpan(Color.RED);
BackgroundColorSpan backgroundSpan = new BackgroundColorSpan(Color.YELLOW);
spannableString.setSpan(foregroundSpan, 0, 8, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
spannableString.setSpan(backgroundSpan, 3, spannableString.length(), Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
textView.setText(spannableString);

进一步的研究

解释SPAN_EXCLUSIVE_EXCLUSIVE等Span标志的含义 Android Spanned, SpannedString, Spannable, SpannableString和CharSequence

从开发人员文档中，更改一个可伸缩对象的颜色和大小:

1-创建类:

    class RelativeSizeColorSpan(size: Float,@ColorInt private val color: Int): RelativeSizeSpan(size) {

    override fun updateDrawState(textPaint: TextPaint?) {
        super.updateDrawState(textPaint)
        textPaint?.color = color
    } 
}

2 .使用该类创建你的spannable:

    val spannable = SpannableStringBuilder(titleNames)
spannable.setSpan(
    RelativeSizeColorSpan(1.5f, Color.CYAN), // Increase size by 50%
    titleNames.length - microbe.name.length, // start
    titleNames.length, // end
    Spannable.SPAN_EXCLUSIVE_INCLUSIVE
)

现在您可以使用CodeView库轻松地突出显示不同颜色的模式，例如，用您只需要编写的蓝色突出显示文本中的所有url

CodeView codeView = findViewById(R.id.codeview);
codeView.addSyntaxPattern(Patterns.WEB_URL, Color.BLUE);
codeView.setTextHighlighted(text);

CodeView存储库URL: https://github.com/amrdeveloper/codeview

有一个用于创建Spannable的工厂，并避免强制转换，就像这样:

Spannable span = Spannable.Factory.getInstance().newSpannable("text");

这是一个帮助函数。当你有多种语言的时候非常有用!

private void setColor(TextView view, String fulltext, String subtext, int color) {
    view.setText(fulltext, TextView.BufferType.SPANNABLE);
    Spannable str = (Spannable) view.getText();
    int i = fulltext.indexOf(subtext);
    str.setSpan(new ForegroundColorSpan(color), i, i + subtext.length(), Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
}